[conradludgate]

My understanding of the way this is presented is that merges don't _block_ the workflow. In git, a merge conflict is a failure to merge, but in this idea a merge conflict is still present but the merge still succeeds. You can commit with conflicts unresolved. This allows you to defer conflict resolution to later. I believe jj does this as well?

Technically you could include conflict markers in your commits but I don't think people like that very much

[anentropic]

If other systems are doing it too then I guess it must be useful

But why is it useful to be able to defer conflict resolution?

I saw in a parallel comment thread people discussing merge commit vs rebase workflow - rebase gives cleaner git history but is a massive pain having to resolve conflicts on every commit since current branch diverged instead of just once on the final result with merge commit.

Is it that? Deferred conflict resolution allows you to rebase but only resolve conflicts at the end?

[shaftway]

Delayed conflict resolution in jj is valuable when you're rebasing a long chain of commits. If I rebase a chain of 10 commits and each of the commits has a conflict, I'm stuck in conflict resolution mode until I fix all 10 conflicts. Maybe something else came up, or maybe I got tired of doing conflict resolution and want to do something else. Git's answer is to finish or abandon.

Also, in jj it's pretty easy to rebase a lot of stuff all at once, giving you even more opportunities to create conflicts. Being able to delay resolution can be easier.

[tcoff91]

Deferred conflict resolution is amazing in jj because I may never return to some of the branches that are in conflict and therefore might never bother resolving them.

I rebase entire trees of commits onto main daily. I work on top of a dev-base commit and it has all kinds of anonymous branches off it. I rebase it and all its subbranches in 1 command and some of those sub branches might now be in a conflicted state. I don’t have to resolve them until I need to actually use those commits.

dev-base is an octopus merge of in-flight PRs of mine. When work is ready to be submitted it moves from being a descendent of dev-base to a parent of dev-base.

Rebasing all my PRs and dev-base and all its descendents is 1 command. Just make sure my @ is a descendent of dev-base and then run: jj rebase -d main

[rightbyte]

> You can commit with conflicts unresolved.

True but it is not valid syntax. Like, you mean with the conflict lines?

[furyofantares]

The conflict lines shown in the article are not present in the file, they are a display of what has already been merged. The merge had changes that were too near each other and so the algorithm determined that someone needs to review it, and the conflict lines are the result of displaying the relevant history due to that determination.

In the example in the article, the inserted line from the right change is floating because the function it was in from the left has been deleted. That's the state of the file, it has the line that has been inserted and it does not have the lines that were deleted, it contains both conflicting changes.

So in that example you indeed must resolve it if you want your program to compile, because the changes together produce something that does not function. But there is no state about the conflict being stored in the file.

[theK]

Isnt that a bit dangerous in its own? If the merge process can complete without conflicts being resolved, doesnt it just push the Problem down the road? All of a sudden you have to deal with failing CI or ghost features that involve multiple people where actually you just should has solved you conflict locally at merge time.

[furyofantares]

The tooling can force resolution at any step desired.

[theK]

What's the point of options when there only is one correct answer?

[furyofantares]

The conflict is no longer an ephemeral part of the merge that only ever lives as markup in the source files and is stomped by the resolution that's picked, but instead a part of history.

I think it is also not true that there's only one correct answer, although I don't know how valuable this is.

For committing let's say yes, only one correct answer. Say the tool doesn't let you commit after you've merged without resolving conflicts.

But continuing to work locally you may want to put off resolving the conflict temporarily. Like person A changed the support email to [e-mail] and person B changed it to [e-mail] - obviously some wires go crossed and I will have to talk to A or B before committing the merge and pushing, but I can also go ahead and test the rest of the merge just fine.

And heck, maybe even committing after merging is fine but pushing requires resolving. Then I can continue working and committing locally on whatever else I was working on, and I'll only resolve it if I need to push. Which may mean I never need to resolve it, because A or B resolve it and push first.

[ericpauley]

Yeah this seems silly. You can do the same thing in git (add and commit with the conflict still there)! Why you would want to is a real mystery.

[fweimer]

It allows review of the way the merge conflict has been resolved (assuming those changes a tracked and presented in a useful way). This can be quite helpful when backporting select fixes to older branches.

[Someone]

In this model, conflicts do not exist, so there are no conflict markers (the UI may show markers, but they get generated from what they call “the weave”)

Because of that, I think it is worse than “but it is not valid syntax”; it’s “but it may not be valid syntax”. A merge may create a result that compiles but that neither of the parties involved intended to write.